Search results for "Amide"
showing 10 items of 3119 documents
Atomic layer deposition of lithium containing thin films
2009
Five different lithium containing compounds, all representing different chemical systems, were studied in order to deposit lithium containing films by atomic layer deposition ALD. The studied compounds were a lithium β-diketonate Li(thd) (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate), a lithium alkoxide LiOtBu (OtBu = tert-butoxide), a lithium cyclopentadienyl LiCp (Cp = cyclopentadienyl), a lithium alkyl n-butyllithium, and a lithium amide lithium dicyclohexylamide. Films containing lithium carbonate (Li2CO3) were obtained from alternate pulsing of Li(thd) and ozone in a temperature range of 185–300 °C. The film composition was analyzed by time-of-flight elastic recoil detection analysis (…
Enantioselective α-alkylation of unsaturated carboxylic acids using a chiral lithium amide
2001
Abstract The regio- and stereochemistry of the alkylation of dienediolates from unsaturated carboxylic acids with benzylic halides, which often results in mixtures of isomers, can be controlled by means of changes in the lithium amide, allowing the α-regioisomer to be obtained as the major diastereoisomer. In addition, when chiral amines are used, moderate enantiomeric excesses can be attained.
Early transition metal derivatives stabilised by the phenylenediamido 1,2-C6H4(NCH2tBu)2 ligand: Synthesis, characterisation and reactivity studies: …
2009
Abstract Li 2 [1,2-C 6 H 4 (NCH 2 t Bu) 2 ] reacts with one equiv of [TiCl 4 (THF) 2 ] in refluxing toluene to give the chelate compound [Ti{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl 2 (THF)] ( 1 ), isolated as a black product, while the reaction of the dilithio diamido salt with one equiv of [ZrCl 4 (THF) 2 ] in refluxing toluene affords the dinuclear zirconium derivative [Zr{1,2-C 6 H 4 (NCH 2 t Bu) 2 }Cl(THF)(μ-Cl)] 2 ( 2 ), obtained as an orange solid. Treatment of the dilithio diamido salt with TaCl 5 in a 2:1 molar ratio in toluene yields [Ta{1,2-C 6 H 4 (NCH 2 t Bu) 2 } 2 Cl] ( 3 ) as a red product. The reaction of 1,2-C 6 H 4 (NHCH 2 t Bu) 2 with [Zr(NMe 2 ) 4 ] in toluene at room temperature …
ChemInform Abstract: Enantioselective α-Alkylation of Unsaturated Carboxylic Acids Using a Chiral Lithium Amide.
2010
Abstract The regio- and stereochemistry of the alkylation of dienediolates from unsaturated carboxylic acids with benzylic halides, which often results in mixtures of isomers, can be controlled by means of changes in the lithium amide, allowing the α-regioisomer to be obtained as the major diastereoisomer. In addition, when chiral amines are used, moderate enantiomeric excesses can be attained.
Multinuclear magnetic resonance, electrospray ionization time-of-flight mass spectral and molecular modelling characterization of lithocholic acid am…
2003
1H, 13C and 15N NMR and electrospray ionization time-of-flight mass spectrometric characterizations of five lithocholate esters of piperazine diamides are described. Two of them are cholaphane-type cyclic structures esterified with 2,2′-bipyridine-4,4 ′ - and pyridine-2,6-dicarboxylic acid and the other three esters are open structures comprising two or four lithocholyl residues. The conformational preferences of the dimeric congeners were examined by using molecular modelling and variable-temperature 1H NMR techniques. Copyright © 2003 John Wiley & Sons, Ltd.
3α-Hydroxy-N-(3-hydroxypropyl)-5β-cholan-24-amide
2009
The title compound, C27H47NO3, is a (3-hydroxypropyl)amide derivative of naturally occurring enantiopure lithocholic acid (3-hydroxy-5-cholan-24-oic acid). The molecule contains four fused rings: three six-membered rings in chair conformations and one five-membered ring in a half-chair form. The two terminal six-membered rings are cis-fused, while other rings are trans-fused. The structure contains an intramolecular O—H O hydrogen bond and a similar hydrogen-bond framework to the corresponding deoxycholic and chenodeoxycholic acid derivatives. Intermolecular O— H O and N—H O interactions are also present in the crystal. This compound seems to have at least two polymorphic forms from a compa…
Systematic Modulation of the Supramolecular Gelation Properties of Bile Acid Alkyl Amides
2018
The self-assembly properties of nine low-molecular-weight gelators (LMWGs) based on bile acid alkyl amides were studied in detail. Based on the results, the number of hydroxyl groups attached to the steroidal backbone plays a major role in the gelation, although the nature of the aliphatic side chain also modulates the gelation abilities. Of the 50 gel systems studied, 35 are based on lithocholic acid and 15 on cholic acid derivatives. The deoxycholic acid derivatives did not form any gels. The gelation occurred primarily in aromatic solvents and the gels manifested typical fibrous or spherical morphologies. The 13C cross-polarized magic angle spinning (CPMAS) NMR spectra measured on the cr…
Bile acid amidoalcohols: simple organogelators.
2003
Simple bile acid amide synthesis of lithocholic and deoxycholic acids with 2-aminoethanol and 3-aminopropanol are reported. The structural properties of these amides were examined by NMR spectroscopic, ESI-TOF mass spectral, and X-ray crystallographic methods. The gelation properties of these amides in common organic solvents and in three different water solutions were also investigated using Tyndall effect, SEM, TEM, and optical microscopy. 2-Hydroxyethylamides were found to be effective gelators in chlorinated organic solvents and 3-hydroxypropylamides in aromatic solvents. Both derivatives thicken neutral and acidic water solutions.
Bile acid alkylamide derivatives as low molecular weight organogelators: systematic gelation studies and qualitative structural analysis of the syste…
2011
A series of amino- and hydroxyalkyl amides of bile acids have been synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), (1)H and (13)C nuclear magnetic resonance spectroscopy (NMR), as well as electrospray ionization mass spectrometry (ESI-MS) measurements. The ability of the synthesized molecules to promote gel formation was systematically investigated. Out of 396 combinations formed by 11 compounds and 36 different solvents, 22 gel-containing systems were obtained with 1% (w/v) gelator concentration. Apart from one exception, the gelator compounds were lithocholic acid derivatives. This challenges the general trend of bile acid-based physical gelators, accordin…
The antifibrotic potential of a sustained release formulation of a PDGF beta-receptor targeted rho kinase inhibitor
2019
Rho kinase activity in hepatic stellate cells (HSCs) is associated with activation, transformation and contraction of these cells, leading to extracellular matrix production and portal hypertension in liver cirrhosis. Inhibition of rho kinase activity can reduce these activities, but may also lead to side effects, for instance systemic hypotension. This can be circumvented by liver-specific delivery of a rho kinase inhibitor to effector cells. Therefore, we targeted the rho kinase inhibitor Y27632 to the key pathogenic cells in liver fibrosis, i.e. myofibroblasts including activated HSCs that highly express the PDGF beta-receptor, using the drug carrier pPB-MSA. This carrier consists of mou…